Safety lock device for quick coupler

ABSTRACT

The present invention relates to a safety lock device for a quick coupler which prevents the coupled state of a work tool installed on a quick coupler at the front of an excavator from becoming arbitrarily released. A safety lock device for a quick coupler according to the present invention is a quick coupler having: a body; a fixed hook formed on one side of the body and having a coupling pin of a work tool inserted therein; and a movable hook provided on a side facing the fixed hook and pivoting according to the actuation of a cylinder to lock another coupling pin of the work tool. Safety locking means are provided on the inside of the body so that the movable hook and the coupling pin of the work tool located within the movable hook are not arbitrarily separated due to the pivoting of the movable hook, firmly maintain a locked state even when a cylinder is damaged during work or transit while the work tool is coupled to the quick coupler, and prevent the work tool from becoming separated or falling from the quick coupler. Thus, accidents causing human casualties and damage to machinery can be prevented, and safety can be ensured.

TECHNICAL FIELD

The present invention relates to a safety lock device for a quick coupler, and in particular to a safety lock device for a quick coupler, which is able to provide a safety which can be much more improved in such a way to prevent the coupled state of a work tool from being arbitrarily uncoupled even when a cylinder is damaged, while an excavator is operating with a work tool coupled, for example, a bucket, a breaker, etc., which in general can be equipped with the aid of a quick coupler.

BACKGROUND ART

The excavator in general is configured to easily and quickly couple or decouple a work tool, for example, a bucket, tongs, a breaker, etc. with the aid of a quick coupler. This work tool can be coupled or uncoupled with the aid of a hydraulic pressure as a driver controls such a coupling or uncoupling work at a driver's chamber. The aforementioned quick coupler is equipped with various devices to prevent a coupled work tool from being arbitrarily uncoupled due to any damage to a cylinder or a malfunction after the work tool, for example, a bucket, has been coupled.

The Korean patent laid-open number 10-2009-0048151 describes a work tool coupling apparatus equipped with a lock device which was invented and filed by the same applicant as the present application, wherein a movable hook 13 which can rotate by the operation of a cylinder 11 and is coupled to an coupling pin 12 a disposed at a portion of a work tool is provided at a lower portion of a body 10, and a fixed hook 14 coupled to another coupling pin 12 b is provided at the opposite portion thereof. A hitch 15 locked by a fixing pin 16 is provided at an outside of the fixed hook 14 so as to prevent any arbitrary unlocking, and a locking pin 17 is inserted in the movable hook 13.

The coupling procedure of the work tool can be completed in such a way that the movable hook 13 is coupled to the coupling pin 12 a by operating the cylinder 11 in a state where the coupling pin 12 b is coupled to the fixed hook 14 at a lower portion of the body 10. The coupling and uncoupling of the work tool can be completed in such a way that the hitch 15 is positioned at an upper portion of the coupling pin 12 b and is fixed with the fixing pin 16, and the locking pin 17 is fixed at the movable hook 13.

According to the aforementioned conventional technology, the coupled state of the work tool is intended to be maintained by coupling the locking pin to the movable hook or the hitch in a state where the quick coupler is coupled to the work tool. In this case, the driver should do such a work after getting out of the excavator or otherwise another worker should couple the coupling pin, which inevitably entails complicated work and long work time. Moreover, if a problem, for example, a cylinder rod is broken during work, occurs, in case where the locking pin is not employed, the hydraulic pressure, which is being applied to the movable hook, may be removed, and for this reason, the movable hook may separate out of the coupling pin, thus unlocking the locked state, whereupon the work tool which is coupled to the quick coupler, may be separated, thus causing any damage to workers or causing a predetermined impact to the excavator or other facilities, which may result in dangerous accidents.

DISCLOSURE OF INVENTION

Accordingly, the present invention is made in an effort to resolve the aforementioned problems. It is an object of the present invention to provide a safety lock device for a quick coupler which is able to provide a safety in such a way to prevent a work tool from falling, which might occur since it is separated or uncoupled from a movable hook or a fixed hook in a state where the work tool is coupled to a quick coupler, even when a cylinder is broken.

To achieve the above object, there is provided a safety lock device for a quick coupler, which may include, but is not limited to, a quick coupler which may include a body; a fixed hook which is provided at a portion of the body, wherein an coupling pin of a work tool is inserted into the fixed hook; and a movable hook which is provided at the opposite of the fixed hook and is configured to rotate by the operation of a cylinder and lock another coupling pin of the work tool, wherein the quick coupler further includes a safety locking means which is provided at an inner portion of the body and is configured to carry out a locking operation in order for the coupling pin of the work tool, which positions within the movable hook and the fixed hook, not to arbitrarily separate as the movable hook rotates.

ADVANTAGEOUS EFFECTS

The present invention is able to provide a safety wherein any accident to workers or any damage to machine or facilities can be prevented, thus securing a safety, since it is possible to prevent a work tool from falling, which might occur since the work tool is separated from a movable hook or a fixed hook or a locked state is unlocked, in such a way that the locked state can be surely maintained even when a cylinder, etc. is broken during a work or a transfer in a state where the work tool is coupled to a quick coupler.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross sectional view illustrating an coupled state of a conventional safety lock device for a quick coupler.

FIG. 2 is a perspective view illustrating the whole configuration of a safety lock device for a quick coupler according to the present invention.

FIG. 3 is a perspective view illustrating a state where a front body plate of a safety lock device for a quick coupler according to the present invention has been removed.

FIG. 4 is a perspective view illustrating a state where a backside body plate of a safety lock device for a quick coupler according to the present invention has been removed.

FIG. 5 is a perspective view illustrating a safety locking unit of a safety lock device for a quick coupler according to the present invention.

FIG. 6 is a schematic cross sectional view illustrating an coupled state when viewing from a front side of the device so as to describe an operation state of a safety lock device for a quick coupler according to the present invention.

FIG. 7 is a schematic cross sectional view illustrating an coupled state when viewing from a backside of the device so as to describe an operation state of a safety lock device for a quick coupler according to the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION

The preferred embodiments of the present invention will be described with reference to the accompanying drawings.

The quick coupler in general is used to carry out a predetermined work, for example, a land excavation, the transfers of timbers, other materials, etc., a land digging, etc. in a state where an upper part of the quick coupler is coupled to a boom, and a lower part thereof is coupled to a work tool, for example, a bucket, tongs, a breaker, etc. A fixed hook which is coupled inserted in an coupling pin of the work tool, is provided at a portion of the quick coupler, and a movable hook which is configured to rotate by the operation of the cylinder so as to carry out a locking or unlocking operation with respect to the coupling pin is provided at the other portion of the quick coupler. The type where the operation direction of the movable hook is pushed, more specifically, it is pushed outward by the cylinder, is called a push type, and on the contrary, the type where the movable hook is pulled by the cylinder, is called a pull type. In the present invention, the push type will be illustrated and described, and the illustration and description on the pull type will be omitted for the sake of simplification.

FIG. 2 is a perspective view illustrating the whole configuration of a safety lock device for a quick coupler according to the present invention. FIG. 3 is a perspective view illustrating a state where a front body plate of a safety lock device for a quick coupler according to the present invention has been removed. FIG. 4 is a perspective view illustrating a state where a backside body plate of a safety lock device for a quick coupler according to the present invention has been removed.

In the drawings, the body 20 is connected, via horizontal reinforcing members 23 and 24, to both ends of each of the front body plate 21 and the backside body plate 22, which are disposed opposite each other, and is fixed by a welding method, etc. A movement hook 25 is fixed at the horizontal reinforcing member 23 between the horizontal reinforcing members 23 and 24 so as to allow an easier movement during the transfer thereof.

Moreover, coupling holes 21 a and 22 a fixed at the boom of the excavator are formed at the front body plate 21 and the backside body plate 22, and a cylinder 26 and a rod 26 a configured to operate by hydraulic pressure are provided at the inner portions thereof. A front end of the rod 26 a is engaged to a pair of the movable hooks 27, so the rod 26 a can move forward or backward by the operation of the cylinder 26, thus moving the movable hooks 27 forward or backward, by means of which the coupling pin of the work tool is locked or unlocked.

The movable hooks 27 are coupled rotatable about the fixing pin 28 which is disposed traversing the front body plate 21 and the backside body plate 22.

A pair of the fixed hooks 29 configured to maintain a locked state by inserting the other coupling pin of the work tool are coupled to the opposites of the movable hooks 27.

An end of each of the fixed hook 29 is coupled to fixing pins 29 a and 29 b, respectively, which are coupled traversing the front body plate 21 and the backside body plate 22, and an end of the cylinder 26 is hinged to the fixing pin 29 a.

A safety locking unit 40 is provided at an inner portion of the body 20 so as to prevent the locked state from being unlocked due to an externally applied load or a damage to the cylinder, etc. in a state where the coupling pins (a) and (b) of the work tool remain locked.

As illustrated in FIG. 5, the safety locking unit 40 may include a moving-side hitch 41 which is engaged to the fixing pin 28 and is rotatable at the opposites of the movable hooks 27, and a fixing-side hitch 42 which is coupled to the fixing pin 29 b and is rotatable at the upper portions of the fixed hooks 29.

The fixing-side hitch 42 is configured to rotate downward with the aid of the elastic force of a spring 43 which is coupled to the fixing pin 29 b, and an end of the spring 43 is supported by an upper portion of the fixing-side hitch 42, and the other end thereof is supported by the body 2.

An operation bar 44 is coupled to a portion of the fixing-side hitch 42, and the operation bar 44 is configured to move rectilinearly within a guide block 45 fixed at an inner portion of the front body plate 21, and an operation roller 46 is coupled to a front end of the operation bar 44, thus moving a contact part 27 a formed at the outsides of the movable hooks 27 in a state where the contact part 27 a is contacting with the operation roller 46.

Moreover, an operation link 50 which can operate in a response to the movement of the operation bar 44 is engaged to the other surface of the fixing-side hitch 42 and to a front end of the moving-side hitch 41.

The operation link 50 may include a first link 51 a front end of which is coupled to a front end of the moving-side hitch 41, a second link 52 a front end of which is hinged to a portion of the fixing-side hitch 42, and a both side-threaded nut 53 which is thread-engaged with the opposite front ends of the first link 51 and the second link 52.

A right hand thread is formed at an inner portion of the both side-threaded nut 53, and a left hand thread is formed at the opposite portion thereof. The right hand thread and the left hand thread are formed at the first link 51 and the second link 52 and are coupled with each other. The whole length of the operation link 50 can be adjusted based on the couplements of the threads.

The aforementioned safety lock device for a quick coupler according to the present invention can carry out a predetermined work after a driver has coupled a work tool, for example, a bucket, a breaker, tongs, etc. based on the kinds of the work in a state where the coupling pin provided at a front end of the boom of an excavator is coupled to the coupling holes 21 a and 22 a formed at the body 20.

When the movable hooks 27 rotate in the counterclockwise direction as in FIG. 6 in a state where the rod 26 a have moved backward, the contact part 27 a will push the front end of the operation bar 44, namely, the operation roller 46, whereby the fixing-side hitch 42 can be opened as indicated by an alternate long and short dash line, and since the fixing-side hitch 42 is opened, the operation link 50 connected thereto can operate, thus opening the moving-side hitch 41.

In the aforementioned state, the fixing-side hitch 42 will be opened upward, and the movable hooks 27 and the moving-side hitch 41 at the opposite thereof will be opened.

The coupling pin (b) is inserted into the fixed hook 29 at a portion of the quick coupler by descending the boom of the excavator, and the coupling pin (a) at the opposite thereof is positioned at a lower portion of the body 20, and the cylinder 26 is moved forward, so the rod 26 a can move forward, and the movable hooks 27 will rotate in the clockwise direction, by means of which the locking can be finished.

When the movable hooks 27 move forward, the contact part 27 a will separate from the operation roller 46, and then the operation bar 44 will become free, whereby the fixing-side hitch 42 will descend in the clockwise direction as in FIG. 6 by the elastic force of the spring 43 and will cover the upper portion of the coupling pin (b), thus obtaining a locked state, and at the same time, the operation link 50 coupled to the fixing-side hitch 42 will move rightward as in FIG. 7, and then the moving-side hitch 41 will rotate in the clockwise direction about the fixing pin 28 and will cover the coupling pin (a), thus obtaining the locked state.

The coupling pin (a) of the work tool will carry out a locking procedure in a posture where it is covered from both sides by the movable hooks 27 and the moving-side hitch 41, and the coupling pin (b) at the opposite thereof will carry out the locking procedure in a posture where it is covered from both sides by the fixed hook 29 and the fixing-side hitch 42, by means of which the locked state won't be arbitrarily unlocked by an externally applied impact or a damage to the cylinder, thus enhancing a lock safety.

Moreover, when it needs to unlock the locked state, the rod 26 a will move backward by the operation of the cylinder 26, and the movable hooks 27 will rotate in the counterclockwise directions, and the contact part 27 a will come into contact with the operation roller 46, thus pushing the operation bar 44, whereupon the fixing-side hitch 42 will rotate upward, and the locked state of the coupling pin (b) will be unlocked. At the same time, the fixing-side hitch 42 will ascend, and the operation link 50 linked thereto will be pulled, so the moving-side hitch 41 at the opposite thereof can rotate and open, whereby the locked state of the coupling pin (a) can be unlocked.

While the present embodiment has been described with the push type quick coupler, it is not limited thereto. It is obvious that the present invention can be adapted to the pull type quick coupler. 

1. A safety lock device for a quick coupler, comprising: a quick coupler which comprises: a body; a fixed hook which is provided at a portion of the body, wherein an coupling pin of a work tool is inserted into the fixed hook; and a movable hook which is provided at the opposite of the fixed hook and is configured to rotate by the actuation of a cylinder and lock another coupling pin of the work tool, wherein the quick coupler further comprises: a safety locking means which is provided at an inside of the body and is configured to carry out a locking operation in order for the coupling pin of the work tool, which is located within the movable hook and the fixed hook, not to arbitrarily separate as the movable hook rotates.
 2. The device of claim 1, wherein the safety lock means comprises: a moving-side hitch which is coupled rotatable at an upper portion of the movable hook and is configured to receive an elastic force from a spring; a fixing-side hitch which is coupled rotatable at an upper portion of the fixed hook; an operation bar which is coupled to a front end of the fixing-side hitch and is transferred by the rotation of the movable hook; and an operation link which is coupled to the moving-side hitch and the fixing-side hitch.
 3. The device of claim 2, wherein the operation bar is configured to be transferred within a guide block fixed at the body since a contact part of the movable hook, which rotates by the operation of the cylinder, pushes a front end thereof, whereby the fixing-side hitch can rotate.
 4. The device of claim 2, wherein an operation roller, which contacts with the contact part of the movable hook, is provided at a front end of the operation bar.
 5. The device of claim 2, wherein the operation link comprises: a first link and a second link, an end of each of which is connected to the moving-side hitch and the fixing-side hitch, respectively; and a both-side threaded nut which is engaged to a front end of each of the first and second links. 